Plastic foams, sometimes also referred to as foamed plastics are known in the art. Plastic foams are typically described in terms of various properties inclusive of density, consistency, i.e. whether flexible or rigid, cellular formation ranging from open to closed, and their electrical, thermal, mechanical and chemical properties. Methods for making plastic foams are likewise known in the art and are exemplified by (1) adding gas to the plastic mass during processing, (2) producing gas in the plastic mass during processing, and (3) forming a plastic mass from granules, to obtain a cellular structure.
Plastic foam products are used for numerous applications and fields such as automobiles, household appliances, packaging, clothing, food, and medical products. These uses are property dependent.
Properties generally required of foam products include light weight, thermal insulating, and cushioning properties. However, with the increasing uses of plastic foam products in new applications, additional properties such as more flexibility and excellent heat resistance are also important. In order to obtain the desired properties, a variety of resins are used in the manufacture of foam products. These resins include low density polyethylene, polystyrene, polypropylene, and poly-1-butene. While these resins have some of the desired properties, they also have certain limitations. For example, low density polyethylene and polystyrene cannot be used at temperatures above 100.degree. C., and polypropylene or poly-1-butene used alone can hardly give a uniform foam with adequate flexibility. In view of these limitations, the need continues to exist to discover resins and/or resin blends which have the desired properties which enables plastic foams made therefrom to be useful in certain applications.